The principles of a scanning confocal microscope are disclosed in U.S. Pat. No. 3,013,467 of Marvin Minsky. The basic principle is that illumination of the specimen or object to be observed is confined to a single point observational field and observation or detection is confined to that illuminated point field. A complete image is derived by scanning the specimen or object under observation point by point through a complete field of view of the microscope.
In early confocal microscopes, including that proposed in the Minsky patent, the optical system remained fixed and scanning was achieved by moving the specimen or object to be observed in a scanning pattern across the focal point of illumination. More recent high speed scanning microscopes have employed beam scanning techniques rather than movement of the specimen. Commonly, these microscopes use a laser as the high illumination light source and have a computer or video system to process and store or display the detected image signals.
Confocal microscopes have better resolution than conventional microscopes and sharper definition in that out of focus signals and interference are much reduced. They have found particular application in the examination of biological specimens by epi-fluorescence where the reduction of out of focus interference is a major advantage.
It is known to produce a confocal microscope by attaching a confocal imaging system to a conventional microscope which provides the condenser or focusing lens for the system. In all known confocal equipment, however, the light condenser the light source and the detector and all of the components defining the optical path for the microscope must be accurately positioned relative to one another and they are therefore all mounted on a bulky common body structure. The present invention provides a modified construction by which some of these components can be positioned completely independently in space without the normal rigid geometric constraints of relative location and orientation. In particular, it enables the light source and the photo-detector to be located in any desired position and without the need for a rigid mechanical connection between them and the remainder of the equipment. Other advantages of the construction provided by the invention will be apparent from the ensuing description.